The Japanese were also held in Canada as well. In fact Germans were held in Canada during WWI and WWII. Ukrainians were held during WWI as well.
Most of it was political, you simply had too many Germans to put them all into a camp. About 120,000 Japanese of which 60% were US citizens (about half nationalize, half born), resided in areas of the US making them eligible to be relocated.
About 10,000 German Immigrants were also held in internment camps. An estimated German immigrant population (on the East coast) would’ve been close to 5 million at the time of WWII, would’ve been eligible to be relocated if the same standards applied. Five million versus 120,000…Well go figure. (that’s immediate immigration form the last few decades, not people with German decent who make up many millions more. Germans are the large plurality of immigrants to America)
Japanese were not held by and by in Hawaii, 'cause it was far too isolated and not worth. Remember air travel was very uncommon, so it wasn’t worth anything to inter Japanese in Hawaii, since they were isolated. The idea was not to use Japanese for cheap labor(though they certainly were used that way), it was to prevent sabotage or collusion
Rationalization could be found simply by the fact Japan attacked us, Germany didn’t. (At least till after the declaration of war). Also Japan occupied several islands of Alaska, Germany didn’t come close to getting any land
Japan was viewed more as a danger to the US than Germany. Churchill was always making sure the main focus of the war effort for the USA was Europe not the Pacific.
Enemy aliens were held in most countries. Enemy doesn’t mean they individually did something, it means they belonged to the ethnic group of an enemy.
We view this as horrible today but historically it’s always been done, even today it’s practiced in a watered down form. For instance, Israeli Arabs don’t serve in Isreal’s military
Internment in camps is less common too. For instance, during the war in Canada, Germans and Japanese were held (and during WWI as well) but at first they were simply required to register. For instance, they were given a card, each month anyone in Canada classed as belonging to such a group would have to go to his local JP or even Postmaster and have his card stamped. This proved he was where he said he was. If he missed this “checking in” he was shipped to a camp.
A lot of misinformation is spread with the internment, of course that doesn’t take away from the fact some people did have their rights violated.
But you have to view it from a historical viewpoint to understand it.
For instance during WWI it there was a mass change of names with people named Braun and such chaning their name to Brown, to make darn well sure eveyone knew who’s side they were on. In NYC there were special courts that helped that process for immigrants.
Can you see anyone doing that now? The Southern USA is the only part of the United States that was involved in a “true” total war. The North during the Civil War and WWII came close to being “total” but even then, the USA was only at a small fraction of it’s total capacity.
As I said I’m not trying to minimize anything here, just saying you need to look at this from a historical persepective.